1. Field of Invention
This invention relates to a touch panel and a method for manufacturing a touch sensor layer of the touch panel, and more particularly to a touch panel and a method for manufacturing a touch sensor layer of the touch panel, wherein transparent electrodes of the touch sensor layer include two transparent metallic patterns which are stacked and electrically connected to each other.
2. Related Art
Recently, the technology of a touch panel is developed quickly. For example, resistance type touch panel, capacitance type touch panel, sound wave type touch panel and optics type touch panel have been widely applied to communication products, computer devices and consumptive electronic products so as to further increase the efficiency and convenience of the applied electronic product.
Referring FIG. 1, it depicts a conventional touch panel 10 includes a touch sensor layer 12 constituted by transparently conductive wires which are disposed longitudinally and transversely, crossed and separated from each other. The touch panel detects an inference of an electric field of the transparently conductive wires generated by a finger, and then reads a sensing signal generated from the longitudinally and transversely transparently conductive wires so as to determine a touch position.
Since transparently conductive materials of transparently conductive wires of the current touch panel are amorphous indium tin oxide (ITO), the patterned ITO is formed by the etching of an oxalic acid during a patterning process (e.g. photolithography and etching process). If the film thickness of the ITO is too thick, the ITO possibly becomes a poly-ITO during a film forming process (e.g. sputtering process). When the poly-ITO is etched by the oxalic acid, some ITO can be still staying. The stayed ITO must be etched by an aqua regia (e.g. nitric acid plus hydrochloric acid). The ITO is restricted by the patterning process, and thus the film thickness of the ITO cannot be too thick.
FIG. 2 is a cross-sectional schematic view of transparent electrodes (X and Y wires along X and Y arrangement directions) of a conventional touch sensor layer. A metal connecting wire 20 is disposed on a transparent substrate 22. An insulating layer 24 is disposed on the metal connecting wire 20 and the transparent substrate 22, and exposes a part of the metal connecting wire 20. A transparent electrode 26 along X arrangement direction and a transparent electrode 28 along Y arrangement direction are disposed on the insulating layer 24, and the transparent electrode 26 along X arrangement direction is electrically connected to the exposed part of the metal connecting wire 20. A protective layer 30 covers an exposed part of the insulating layer 24, the transparent electrode 26 along X arrangement direction and the transparent electrode 28 along Y arrangement direction. However, the transparent electrode 26 along X arrangement direction and the transparent electrode 28 along Y arrangement direction are restricted by the fact that the film thickness of the ITO cannot be too thick, and thus the transparent electrode of the touch sensor layer along X and Y arrangement directions have higher resistance.
Accordingly, there exists a need for a touch panel capable of solving the above-mentioned problems.